Could you put portions into FoodSaver, e.g., bags or containers and do the vacuum sealing thing? If I'm understanding it correctly, that would allow you to store in the fridge for extended periods.

I bought my system for parcelling up roasts, like ham that doesn't freeze well, so I could store them safely in the fridge instead. Wouldn't that work for a cream soup or sauce?

In a word: no. Do the vacuum sealing thing for frozen foodstuffs which can't endure freezer burn. A ham or roast in the fridge ain't gonna last very much longer shrink wrapped in FudSaver than it would in newspaper, though it will look much prettier when it gives you ptomaine.

Only exception I can think of is for a dry grated cheese, like Parmesan; and then you need to use a mason jar and a lid -- and the optional, additional attachment.

I bought my system for parcelling up roasts, like ham that doesn't freeze well, so I could store them safely in the fridge instead. Wouldn't that work for a cream soup or sauce?

Low cost vacuum sealers work by sucking air out of special bags with ridges on one side which act as air channels. The problem with this technique is that air pressure outside of the bag will try to squeeze everything out of the bag that can be squeezed out through the plastic channels... including all liquids. The only way to use a FoodSaver or equivalent vacuum sealer is to vacuum seal them in special FoodSaver containers or in mason jars with the mason jar attachment. That will help extend the life of the soup in the fridge by a few weeks if everything was sterilized.

I like to sweat the onion/leek mixture in butter and olive oil, and add either diced celeriac or potato. After 15-20 minutes sweating, add the stock of choice and boil/pressure cook until all tender. Meanwhile, finely chop mushrooms and sweat in a little butter and olive oil. Combine the two and blend/liquidise. No flour, because the celeriac or potato absorbs the fat. Add creme fraiche or cream to taste, or indeed some coarsely chopped mushroom as done here. Chopped parsley is also good at the end.